1. Field of the Invention
The present invention relates to a method of fabricating a part comprising a conductive material and a part used in a sensor, an actuator or the like, comprising a conductive material and including a structure having a movable portion in the fields of a metal industry, a chemical industry, an electronic industry, a machine industry and the like.
2. Description of the Related Art
A conventional method of fabricating a part with a desired shape is generally performed by removing an unnecessary portion of a fabricating material utilizing mechanical machining technology or electric discharge machining technology. In a method utilizing mechanical machining technology, such as a cutting tool, by rotating either the cutting tool or the fabricating material and, at the same time, bringing the cutting tool and the fabricating material into contact with each other, the unnecessary portion of the fabricating material is removed to thereby finally obtain a part having a desired shape. Meanwhile, in a method utilizing electric discharge machining, a machining electrode having a front end shape in correspondence with a desired fabricating shape is produced, an interval between the machining electrode and the fabricating material is adjusted to a predetermined distance and by repeatedly producing an electric discharge in a pulse-like shape therebetween, a desired shape is achieved by removing the unnecessary portion of the fabricating material to thereby fabricate a part.
Meanwhile, a method of fabricating a part partially including a movable portion is generally performed by fabricating the individual elements utilizing various fabrication technologies such as mechanical machining technology and electricity discharge machining technology, described above, and thereafter, assembling the elements.
Further, in addition to such methods, and as shown by FIG. 3 and FIG. 4, there is generally used a method of forming a movable portion by a method of patterning a thin film or a thick film deposited on a substrate in a layered shape by photolithography. When the movable portion is formed by the method shown in FIG. 3 and FIG. 4, the following procedure is carried out.
At a portion of a flat base substrate 101, there is deposited a sacrificing layer 102 comprising a material different from that of the base substrate 101 by a predetermined thickness (FIG. 3(B)). Further, on the sacrificing layer 102, there is deposited a structural body material layer 103 comprising a material different from that of the sacrificing layer 102 by a predetermined thickness (FIG. 3(C)). Successively, the structural body material layer 103 is patterned into a desired shape.
First, a photoresist 301 is coated on the structural body material layer 103 (FIG. 3(D)) and light is irradiated to the photoresist 301 via a photomask 302 having a pattern to be formed at the structural body material layer 103 to thereby expose the photoresist 301 (FIG. 3(E)). Thereafter, there is formed a mask pattern for patterning the structural material layer 103 on the photoresist 301 by being subjected to steps of development, rinsing, post baking and so on (FIG. 4(A)). In such a state, the substrate is dipped in an etching solution for dissolving the structural body material layer 103 to thereby etch a portion of the structural material layer 103 that is not coated by the photoresist 302. When there is constituted a state (FIG. 4(B)) in which the portion of the structural body material layer 103 which is not coated by the, photoresist 302 is penetrated to reach the sacrificing layer 102, successively, the substrate is dipped in an etching solution which does not dissolve the base substrate 101 and the structural body material 103 and selectively dissolves only the sacrificing layer 102 to thereby remove the sacrificing layer 102 formed at the step of FIG. 3(B) (FIG. 4(C)). Finally, the photoresist 301 is removed and in, a structural body material layer 103 a movable portion 202 that is not tightly attached to the base substrate 101 can be formed (FIG. 4(D)). In a state shown by FIG. 4(D), a quadrangle of the movable portion 202 is only connected to a structural body fixing portion 201 via narrow beams and therefore, when force is applied to the movable portion 202, the movable portion 202 is moved relatively to the base substrate 101 only by an amount in proportion to the force. Such a structure is utilized in, for example, a pressure sensor or an acceleration sensor.
However, there are a number of problems in the conventional part fabricating method. When the mechanical machining technology is utilized to the part fabricating method, there are following problems.
(1) Most of the fabricating material is removed and wasted to make a final shape of a part. Further, a long fabrication period of time is taken.
(2) A machinable shape is restricted depending on a kind of a fabricating machine used and therefore, in the case of fabricating a part having a complicated shape, many kinds of fabricating machines are needed and a number of steps of fabrication increases.
(3) The machining is carried out by bringing the cutting tool and the fabrication object into contact with each other and therefore, dissipation of the cutting tool is unavoidable. When the cutting tool is dissipated, there are problems caused, in that accuracy of fabrication is deteriorated, a fabricating surface is roughened and so on, therefore, the cutting tool is changed as necessary.
(4) Since fabrication is carried out by utilizing physical force produced between the cutting tool and the fabrication object and therefore, machinability is affected to hardness and tenacity of the fabrication material. Therefore, kinds and fabrication conditions of the cutting tool need to adjust in proportion to the material of the fabrication object.
(5) Smaller tip size of the cutting tool gives higher tip resolution of fabrication. However, there is a limit in miniaturizing tip size of the cutting tool because fabrication is carried out utilizing physical force. Further, similarly, it is necessary that the fabrication object is not deformed by the physical force operated in fabrication and therefore, there is a limit in a size of a machinable part.
Next, when the electro discharge machining technology is utilized to the part fabricating method, there are following problems.
(1) The fabrication shape is determined by the shape of the machining electrode, and therefore, it is necessary to fabricate the machining electrode having a appropriate shape in correspondence with a desired shape of machining. Usually, in fabricating the machining electrode, a wire cut electro discharge machine is used, two kinds of electro discharge machines are needed for fabricating the machining electrode and fabricating the part. Therefore, fabrication cost is increased.
(2) Similarly to mechanical machining, dissipation of the machining electrode is unavoidable and the machine electrode is changed as necessary. Further, in fabrication, position of the machining electrode has to be controlled in consideration of dissipation of the machining electrode. Therefore, the control method becomes complicated.
(3) In most of the cases, similarly to mechanical machining, most of the fabrication material is removed and wasted to make a final shape of a part. A long period of fabrication time is taken.
(4) In order to create a discharge, a high voltage needs to be applied, and therefore, energy consumption in fabrication is considerable. Further, there is a risk of producing a damaged layer on the surface after fabrication by discharge.
Further, in the case of fabricating a part that includes a movable portion according to the conventional method, the following problems have arisen. First, in the case of the method which includes the process of fabricating the individual elements constituting the part by utilizing various fabrication technologies such as mechanical machining technology or electro discharge machining technology, and the assembling the individual elements, there is a need to assemble the individual elements. Therefore, as a size of a part becomes smaller, a size of an element for constituting the part also becomes smaller, and there is a problem in that the element is distracted in assembling, or the element cannot be assembled while maintaining accuracy. In order to resolve such problems, it is necessary to use a manipulator that is capable of fine positioning operation. This makes fabrication cost higher.
Next, in the case of forming movable portion of a part by the method of patterning a thin film or a thick film deposited on a substrate in shape of a layer by photolithography, the method better previous methods because the assembly operation is not needed, and is effective even when a part is downsized.
However, in the case of the foregoing method, when the thickness of the structural body material 103 is increased, in the step of a etching the structural body material 103 shown in FIG. 4(B), there are problems in that by etching the substrate down to a lower side of the resist pattern *undercut), accuracy of a shape of the pattern is deteriorated and the substrate is dipped in the etching solution for a long period of time and therefore, there is needed a resist material having a resistance against the etching solution for the time period and so on. Among them, with regard to the former, the problem can be avoided by adopting a method of using a material or an etching solution having an anistotropy in the etching direction, however, in such a case, it is necessary to use a material having such a property in the structural body material 103 and therefore, a width of selecting the material is narrowed. Further, in order to expose the photoresist 301 to a desired pattern, it is necessary to previously fabricate the photomask 302 in conformity therewith and it is extremely difficult to fabricate a shape of the structural body material 103 in an arbitrary shape at the site. For example, in the case of optimizing the shape of the structural body material 103 in view of characteristics after fabrication, it is necessary to form a number of photomask patterns beforehand and there poses a problem that much of time and cost is take to achieve an optimum result.
According to the method of fabricating a part of the invention, there is provided means for resolving the above-described problem.
According to a first aspect of the invention, there is provided a method of fabricating a part comprising a sacrificing layer forming step of depositing a layer of a material for constituting a sacrificing layer on a surface of a base material, a structural body material layer forming step of depositing a layer for constituting a material of a part structural body different from the sacrificing layer on a surface of the sacrificing layer, a part shape fabricating step of the structural body material layer along an outer configuration shape of the part, and a part separating step of separating the structural body material fabricated in an outer configuration of the part from the base material by selectively removing only the sacrificing layer, wherein the part shape fabricating step is carried out by a chemical fabricating process.
According to a second aspect of the invention, there is provided a method of fabricating a part comprising a structural body material layer forming step of depositing a layer for constituting a material of a part structural body different from a base material on a surface of the base material, a part shape fabricating step of fabricating the structural body material layer along an outer configuration shape of the part, and a part separating step of separating the structural body material fabricated in an outer configuration of the part from the base material by selectively removing a portion or a total of the base material, wherein the part shape fabricating step is carried out by a chemical fabricating process.
Further, according to a third aspect of the invention, there is provided a method of fabricating a part comprising a peeling layer forming step of forming a peeling layer on a surface of a base material by subjecting the base material to a surface treatment, a structural body material layer forming step of depositing a layer for constituting a material of a part structural body on a surface of the peeling layer, a part shape fabricating step of fabricating the structural body material layer along an outer configuration shape of the part, and a step of separating the structural body material fabricated in an outer configuration of the part from the base material at the surface of the peeling layer, wherein the part shape fabricating step is carried out by a chemical fabricating process.
Further, according to a fourth aspect of the invention, there is provided in the method of fabricating a part according to any one of the first to the third aspects, wherein the part shape fabricating step includes a step of separating only the part from the structural body material layer by forming a groove having a predetermined width at the structural body material layer along the outer configuration shape of the part by a chemical fabricating process.
Further, according to a fifth aspect of the invention, there is provided a method of fabricating a part wherein in the fourth aspect of the method of fabricating a part, the chemical fabricating process used in the part shape fabricating step comprising a step of arranging a machining electrode having a pertinent shape in a machining solution oppositely to the structural body material layer, and a step of moving at least one of the machining electrode and the structural body material layer relatively to each other by a path in correspondence with a shape to be fabricated while applying a pertinent voltage between the structural body material layer and the machining electrode.
Further, according to a sixth aspect of the invention, there is provided a method of fabricating a part constituted by a base material and a structural body material layer formed thereon, a portion of the structural body material layer forming a structural body fixing portion which is tightly attached to the base material and the structural body material layer except the structural body fixing portion not being tightly attached to the base material and including a movable structure capable of changing a position thereof relative to the base material, the method comprising a sacrificing layer forming step of depositing a layer of a material, for constituting a sacrificing layer on a surface of the base material, a structural body fixing portion forming step of forming the structural body fixing portion by exposing the surface of the base material by removing a portion of the sacrificing layer a structural body material layer forming step of depositing a layer for constituting a material of a part structural body different from the sacrificing layer on surfaces of the sacrificing layer and the structural body fixing portion, a movable portion shape fabricating step of fabricating the structural body material layer along an outer configuration shape of the movable portion, and a movable portion separating step of separating the structural body material layer except the structural body fixing portion from the base material by selectively removing only the sacrificing layer, the movable portion shape fabricating step is carried out by a chemical fabricating process.
Further, according to a seventh aspect of the invention, there is provided a method of fabricating a part constituted by a base material and a structural body material layer formed thereon, a portion of the structural body material layer forming a structural body fixing portion which is tightly attached to the base material and the structural body material layer except the structural body fixing portion not being tightly attached to the base material and including a movable structure capable of changing a position thereof relative to the base material, the method comprising a sacrificing layer forming step of depositing a layer of a material for constituting a sacrificing layer on a surface of the base material except an area for constituting the structural body fixing portion, a structural body material layer forming step of depositing a layer for constituting a material of a structural body different from the sacrificing layer on surfaces of the sacrificing layer and the structural body fixing portion, a movable portion shape fabricating step of fabricating the structural body material layer along an outer configuration shape of a movable portion, and a movable portion separating step of separating the structural body material layer except the structural body fixing portion from the base material by selectively removing only the sacrificing layer, and the movable portion shape fabricating step is carried out by a chemical fabricating process.
Further, according to an eighth aspect of the invention, there is provided a method of fabricating a part constituted by a base material and a structural body material layer formed thereon, a portion of the structural body material layer forming a structural body fixing portion which is tightly attached to the base material and the structural body material layer except the structural body fixing portion not being tightly attached to the base material and including a structure capable of changing a position thereof relative to the base material, the method comprising a peeling layer forming step of forming a peeling layer on a surface of the base material except an area for constituting the structural body fixing portion, a structural body material layer forming step of depositing a layer for constituting a material of a structural body on surfaces of the peeling layer and the structural body fixing portion, a movable portion shape fabricating step of fabricating the structural body material layer along an outer configuration shape of a movable portion, and a movable portion separating step of separating the structural body material layer except the structural body fixing portion from the base material at the surface of the peeling layer, wherein the movable portion shape fabricating step is carried out by a chemical fabricating process.
Further, according to a ninth aspect of the invention, there is provided a method of fabricating a part, wherein in the method of fabricating a part according to the sixth through the eighth aspects, the movable portion shape fabricating step includes a step of forming a shape of the movable portion in the structural body material layer by forming a groove having a predetermined width in the structural body material layer along an outer configuration shape of the movable portion by a chemical fabricating process.
Further, according to a tenth aspect of the invention, there is provided a method of fabricating a part, wherein in the ninth aspect of the method of fabricating a part, the chemical fabricating process used in the part shape fabricating step comprising a step of arranging a machining electrode having a pertinent shape in a machining solution oppositely to the structural body material layer, and a step of moving at least one of the machining electrode and the structural body material layer relatively to each other by a path in correspondence with a shape to be fabricated while applying a pertinent voltage between the structural body material layer and the machining electrode.